Process of coating with metal.



UNITED STATES PATENT ()FFICE.

CHARLES E. MUIWEQOE, OF WASHINGTON, DISTRICT OF COLUMBIA, ASSIGNOR TOKUHN FORMALDEHYDE GENERATOR COMPANY, A CORPORATION OF VIRGINIA.

PROCESS 0F COATING WITH METAL.

SPECIFICATION forming part of Letters Patent No. 724,317, dated March31, 1903.

Application filed September 6,

, Metal, of which the following is a description.

Myinvention relates to the formation upon surfaces of metal orotherinorganic material of a coating of a metal or its oxids in afinelydivided state; and it consists in the hereinafterdescribed processof producing such a coating by the use of a soluble compound of themetal and a soluble compound with which the compound of the metal willreact to form a precipitate and subsequently decomposing theprecipitate.

My process while not confined to any particular purpose is particularlyadapted to the formation upon perforated sheets or disks of asbestos andupon sheets or disks of perforated metal or woven wire of a coating offinely-divided platinum to adapt such plates or disks to be used in theslow combustion of methyl alcohol for the purpose of generatingformaldehyde, and m y'invention is herein de-- scribed as applied tothis purpose.

In carrying out my in vntion I take a sheet of the material on which thecoating is to be formed--as,'for instance, a sheet of asbestos havingperforations therein to adapt it to be used in aformaldehyde-genorator-and immerse the sheet in an alcoholic solution ofammonium chlorid and then immerse it in an alcoholic solution ofplatinic chlorid, though, if preferred, the sheet may be first immersedin the platinic chlorid and subsequently in the ammonium chlorid. Theresult produced, which is the same whether the ammonium chlorid or theplatinic chlorid is first used, is a reaction of the two compounds,forming upon the surface of the asbestos a crystalline precipitate ofthe 'ammonium-platinic-chlm rid. When the precipitate has been formed, Iheat thesheet of asbestos. The heat acts first to drive offthe alcoholand then decom-" Serial lib-122,403. (No specimens.)

metal in a very finely-divided state upon the surface of the asbestos.

By reason of the fact that the double plati num salt formed bythe'reaction of the ammonium chlorid and platinic chlorid is practicallyinsoluble in alcohol the precipitate will be formed, as above stated,upon the surface of the asbestos and not throughout the body of thematerial, thus avoiding the use of any greater quantity of platinum thanis necessary and producinga uniform finely-divided or porous coatingupon the surface only, so as to secure the maximum catalytic efiect withthe minimum expenditure of platinum.

Having thus described my invention, what I claim, and desire to secureby Letters Patent of the United States,.is

1. The process of forming upon metallic or metal which consists insuccessively immersing the body to be coated in a solution of a compoundof the metal and in a solution of a compound adapted to react upon thecompound of the metal to form a crystalline compound of the metal, andsubsequently heating the body thus coated; substantially as described.

2. The process of forming upon the surface of asbestos, a coating offinely-divided platinum which consists in successively immersing theasbestos in a solution of platinic chlorid and in a solution of ammoniumchlorid and subsequently heating the asbestos; substantially asdescribed.

3. The process of forming upon the surface of asbestos, a coating offinely-divided platiing the asbestos inan alcoholic solution of platinicchlorid and in an alcoholic solution of ammonium chlorid andsubsequentlyheating the asbestos; substantially as described.

p i In testimony whereof I affix my signature in presence of twowitnesses.

CHARLES E. MUNROE.

Witnesses:

A. P. GREELEY, GRAFTON L. MoGILL;

other surfaces a coatiugof finely-divided num which consists insuccessively immers-

